Water-soluble CdTe QDs were synthesized in aqueous solution with thioglycolic acid as the stabilizer by one step. A new approach was studied on the determination of silver ions with quantum dots as fluorescence probes based on the fluorescence quenching method. The silver ions quenched the FL intensity and the quenching effect could be described by Stern-Volmer-type equation. The limit of detection of silver ions was 3 × 10~(-8) mol/L. Water-soluble CdTe QDs were selective to silver ions and might be u...